LAUSR

This paper addresses the parameter identification problem of a damping model applied to a nonlinear chaotic system. The chosen system is a passively-actuated tilted Furuta pendulum. The pendulum is tilted to ensure the existence of a stable equilibrium configuration for all its degrees of freedom, and the link weights are the only external forces applied to the system. A nonlinear analytical model of the pendulum is derived, and a continuous friction model taking into account static friction, dynamic friction, viscous friction, and the stribeck effect in the joints is chosen from literature. A high-gain Universal Adaptive Stabilizer observer is designed to identify friction model parameters using joint angle measurements. The methodology is tested in simulation and validated on an experimental setup. Despite the high nonlinearity of the system, the methodology is proven to converge to the correct parameters in simulation and to give qualitative parameter magnitudes in experiments. The discrepancy between simulation and experimental results is attributed to the limitations of the friction model, which can be extended to others as no unified friction model exists in literature. The main advantage the proposed method provides is the significant reduction in computational needs and time required relative to conventional optimization-based identification routines.